The carbonaceous feedstock gasification facility is a facility that converts carbonaceous feedstock into gas mainly containing CO, H2, and the like by gasifying agent containing oxygen, steam, or the like.
A conventional carbonaceous feedstock gasification facility generally includes a carbonaceous feedstock feeding system, a gasifier, and a char recovery system. The carbonaceous feedstock is fed to the gasifier by carrier gas such as nitrogen and receives gasifying agent (air, oxygen-enriched air, oxygen, steam, etc.). Then, in the gasifier, the carbonaceous feedstock is subjected to gasification under combustion to generate product gas (combustible gas). The product gas is fed to the char recovery system, where unreacted carbon-containing feedstock (char) is removed.
The char recovery system in the carbonaceous feedstock gasification facility removes, from the product gas generated in the gasifier, the char contained in the product gas using a plurality of stages of precipitators. The recovered char is returned, in increments of a prescribed amount, to the gasifier by a char feeding unit. That is, a bin system is used here. A common bin system includes a single (or plurality of) bin, a plurality of char discharge lines that discharge the char recovered by the precipitators into the bin, and a plurality of char feeding lines that feed the char recovered in the bin to a plurality of (or a single) hoppers.
There are known, as the conventional char recovery system, those described in Patent Literatures 1 to 3 described below.
By the way, in order to respond to an increase in an amount of aeration gas due to an increase in plant capacity, the char recovery system needs to be provided in plural numbers. Further, the char feeding hopper also needs to be provided in plural numbers in order to respond to an increase in char flow rate due to the increase in plant capacity.
Further, in order to ensure reliability of each unit, the number of, e.g., hopper configurations needs to be increased from two (minimum required number) to three, four, . . . .
In order to achieve the above hopper configuration, it is necessary to connect the char recovery system and a char bin for storing the char from char separation means by a delivery tube.
Sometimes, a valve is installed between the char recovery system and char bin. In this case, a gate valve and an air-tight valve need to be connected to a char bin outlet and a feeding hopper inlet, respectively. Further, an expansion joint is installed in order to absorb thermal elongation between the hoppers.
The char recovered by the char recovery system is fed to the char feeding hopper and is then reintroduced into the gasifier with hopper pressure made higher than gasifier pressure by a specified value.
In order to perform operation control so as to substantially balance between an amount of recovered char and a feeding amount of the char in the reintroduction of the recovered char into the gasifier, a load cell is installed in all the char feeding hoppers to measure a char weight.